Difference between graphite electrode and copper electrode

More and more customers, while using traditional copper electrodes for EDM, are beginning to realize some new trends of technological change: “How can we apply limited resources to increase production value, and how can we save time, cost and energy in the same situation?” Graphite electrode as EDM electrode material, with its high cutting, light weight, fast forming, very small expansion rate, small loss, easy to repair and other advantages, is due to its special stable physical properties and gradually become the future trend of EDM electrode material, has been widely used in the mold industry, instead of copper electrode has become inevitable.

The difference between graphite electrode and copper electrode:

1. Some special shaped electrodes cannot be made of copper. Choosing graphite electrode has good mechanical processing ability and can achieve complex geometric shapes.The graphite electrode is easy to clamp and can completely eliminate the process of wire cutting. In addition, copper electrodes are relatively heavy (the specific gravity of graphite and copper is 1.9:8.9), which is not suitable for processing large electrodes.

2. Graphite is divided into different grades, and using appropriate grades of graphite and spark machine discharge parameters in specific applications can achieve ideal machining results.This is because the melting point of copper is 1083 ℃, while graphite only sublimates at 1083 ℃. Therefore, graphite electrodes can withstand larger machine settings. If the material of the electrode can be strictly controlled, graphite electrodes can be set to a non loss state (loss less than 1%) during rough machining, but copper electrodes are not used.

The design of graphite electrodes is also different from that of traditional copper electrodes. Many mold factories usually have different reserved amounts for rough and precision machining of copper electrodes, while graphite electrodes use the same reserved amount, which reduces the number of CAD/CAM and machine processing times. This alone is enough to greatly improve the accuracy of mold cavities.

4. Discharge accuracy: Many automotive molds and plastic product molds are processed using special grade graphite through EDM, which eliminates the need for mold cavity polishing and chemical polishing processes while still achieving the expected surface smoothness. Without increasing the time and polishing process, copper electrodes cannot produce such workpieces.

5. The milling time of graphite electrode is 67% faster than that of copper electrode, and the discharge rate and removal rate of electrical discharge machining are higher than that of copper electrode. In general, using graphite electrode is 58% faster than using copper electrode in electrical discharge machining, which significantly reduces processing time, shortens mold cycle, and also reduces manufacturing costs.